Prime Rib Dip Recipe

Prepare onion

Peel the yellow onion and slice it into 1/8- to 1/4-inch thin half-moons so they cook evenly.

Heat a skillet over medium heat. Add 1 tablespoon olive oil and 1 tablespoon unsalted butter. When butter is melted and foamy, add the sliced onions in an even layer.

Sprinkle 1/4 teaspoon salt, 1/4 teaspoon black pepper, and optional 1/2 teaspoon granulated sugar over the onions. Stir to combine and cook, stirring every 2–3 minutes, until softened and golden brown, about 12–18 minutes. If onions begin to brown too quickly, reduce heat to medium-low.

Once nicely caramelized and soft, remove from heat and keep warm until assembly.

In a small saucepan set over medium heat, combine 2 cups beef au jus (or low-sodium beef broth), 1/4 cup dry red wine (if using), 2 tablespoons beef drippings (or butter), 1 teaspoon Worcestershire sauce, 1 sprig fresh thyme, and 1 peeled garlic clove smashed with the side of a knife.

Bring mixture to a gentle simmer, scraping up any browned bits from the bottom if using drippings. Simmer for 6–8 minutes to meld flavors. Taste and adjust seasoning with a pinch of salt and pepper if needed.

If you prefer a slightly thicker jus, make a slurry by whisking 1 teaspoon cornstarch with 1 tablespoon cold water until smooth. Whisk the slurry into the simmering jus and cook 1–2 minutes until slightly thickened. Remove thyme sprig and discard. Keep the au jus warm in the saucepan or transfer to a small dipping bowl.

If the prime rib is refrigerated, remove it 20–30 minutes before warming to take off the chill. Pat the slices dry with paper towels and season lightly with the remaining 1/2 teaspoon salt and 1/2 teaspoon black pepper.

Preheat a large skillet or griddle over medium heat. Add 2 tablespoons unsalted butter and let it melt and foam.

Add the prime rib slices in a single layer (work in batches if necessary). Warm the slices for about 1 minute per side — you want them heated through and slightly browned at the edges but not overcooked. Remove warmed slices and keep loosely tented with foil to stay warm.

Split the hoagie rolls lengthwise without cutting all the way through. Lightly butter the cut faces if desired and toast them, cut-side down, in the same skillet for 1–2 minutes until golden and slightly crisp.

Lay 3–4 warmed prime rib slices into each hoagie roll, top each with a portion of the sautéed onions and one slice of Monterey Jack cheese.

If you want the cheese melted, place the assembled sandwiches on a baking sheet and broil on high for 1–2 minutes (watch closely) or return to the skillet with a lid for 1–2 minutes until cheese has softened and melted.

Serve immediately with the warm au jus in small bowls alongside for dipping.